Dew Point vs. Relative Humidity — In Plain Words
General information only.
Short answer
If you want a real judge of just how “dry” or “humid” it will feel outside, look at the dew point instead of the relative humidity.
The higher the dew point, the muggier it will feel.
What this page covers
This page explains the difference between the dew point and relative humidity, in plain words. It is based on one page from the National Weather Service: “Dew Point vs Humidity,” from the Weather Service office in La Crosse, Wisconsin.
Cross-reference, in plain text only: See also the companion guide about the heat index — the heat index combines temperature and humidity into one “feels like” number; this page is about the dew point number itself.
What the dew point is
The dew point is the temperature the air needs to be cooled to (at constant pressure) in order to achieve a relative humidity (RH) of 100%.
At this point the air cannot hold more water in the gas form. If the air were to be cooled even more, water vapor would have to come out of the atmosphere in the liquid form, usually as fog or precipitation.
The higher the dew point rises, the greater the amount of moisture in the air. This directly affects how “comfortable” it will feel outside.
Why relative humidity can be misleading
Many times, relative humidity can be misleading. For example, a temperature of 30 and a dew point of 30 will give you a relative humidity of 100%, but a temperature of 80 and a dew point of 60 produces a relative humidity of 50%.
It would feel much more “humid” on the 80 degree day with 50% relative humidity than on the 30 degree day with a 100% relative humidity. This is because of the higher dew point.
So the relative humidity number alone does not tell you how humid it will feel. The dew point does.
Summer comfort levels, using dew point
The National Weather Service gives these general comfort levels using dew point, that can be expected during the summer months:
- Less than or equal to 55: dry and comfortable.
- Between 55 and 65: becoming “sticky” with muggy evenings.
- Greater than or equal to 65: lots of moisture in the air, becoming oppressive.
That is the whole comfort scale as the Weather Service states it on this page: three bands, and nothing finer.
Sources
Source used for this page:
- National Weather Service, La Crosse, WI office, “Dew Point vs Humidity”: https://www.weather.gov/arx/why_dewpoint_vs_humidity
The official page this guide rests on is short, and this guide adds nothing from outside it.
Checked November 2, 2026.
General information only.